The present invention concerns a unique method for fabricating garments made of fabrics whose essential and primary fiber is cotton to produce garments having attributes far superior to those produced by present conventional methods. The finished garments made according to the inventive process will have significantly less shrinkage than those conventionally produced when laundered and subjected to tumble drying. The garment at point-of sale has: superior fit that is, has not been made significantly oversized or need not be purchased oversized by the consumer to allow for subsequent shrinkage; garments produced by the invention have remarkably soft hand and there is much less deterioration of the cotton fabric's tensile and burst strength characteristics which, invariably, results from conventional use of resins to control shrinkage.
Heretofore shrinkage control of cotton fabric, particularly 100% cotton fabric has been achieved to a greater or lesser extent by the use of mechanical preshrinkage techniques which generally compact or crimp the cotton fibers of woven or knitted fabric, thereby attempting to place such fabric in a less shrinkable condition. Such mechanical preshrinkage is accomplished by the use of rubber belts, shoes, rollers, stuffing boxes, doctor blades and the like. Mechanical preshrinkage systems have certain drawbacks. Generally speaking, fabric is processed at relatively slow speeds which inhibit production; and the process of subjecting tubular knit fabric to mechanical compaction invariably provides a "one-sidedness" to the fabric which creates problems when the fabric is cut and sewn and made into finished garments. Further, a knit garment composed of various styles or constructions may have some parts compacted and with luster and additional one-sided effects and others, for example, ribs and collars that are not and cannot be subjected to compaction, will differ in appearance from a visual and feel point of view and thus is undesirable. Compacting is not effective on resinated and fully-cured fabrics. Moreover, mechanical preshrinking systems are generally fairly expensive because of the capital investment in equipment and reduced production speed.
With the advent of polyester/cotton blends and the resin treatment of fabrics to provide durable press or wash and wear characteristics, less need has existed to resort to mechanical shrinkage control since the synthetic fibers can be heat set and resin treatment of the cotton component further imparts a degree of shrinkage stabilization.
It has been known for a number of years that cross linking chemicals can be used in order to impart shape-holding properties - wrinkle resistance, wash-wear properties and above all dimensional stability. The present art of crosslinking finishes or resins as they are called in the trade evolved around formaldehyde-based condensation products with urea or urea derivatives. The chemistry and manufacturing methods are well known to those involved in the textile trade. Examples of some of the chemicals used or being used are given below:
dimethylolurea, dimethylol ethylene urea, dimethylol alkyl carbamate, trimethylolmelamine, dimethylol dihydroxyethylene urea, and modified or substituted dimethylol dihydroxy ethylene ureas.
The chemical structure of the last product which is being used very widely at present is as follows: ##STR1## where R.dbd.--H (dimethylol dihydroxy ethylene urea) or --CH.sub.3, or --R'--OH. It is beyond the scope of this description to give details of the chemistry and properties of various formaldehyde-based adducts as cross linking agents. They are described in detail in well known published textbooks and articles such as "Crease Resisting Fabrics" by J. T. Marsh, Reinhold Publishing Corporation, New York, 1962, "Chemical Aftertreatment of Textiles" Edited by H. Mark, Norman S. Wooding and Sheldon M. Atlas, Wiley Inter-Science, a Division of John Wiley and Sons, Inc., New York, 1971, and 2-Imidazolidinones (Ethylene Ureas)--A review by P. K. Shenoy and John W. Pearce, American Dyestuff Reporter, May 6, 1968. At present, the chemical methods to control the shrinkage of cotton fabrics or garments is by the use of crosslinking resins, hereafter referred as resins, such as DMDHEU (dimethylol dihydroxy ethylene urea) or modified derivatives. However, resination of fabric is not fully effective. In order to achieve a degree of shrinkage control of say, no more than five percent, producers of fabric must use approximately fifteen to twenty-five percent of resin by weight of fabric. This amount of resin will reduce the tear and burst strength of cotton fiber by about fifty percent. Moreover, the resin imparts a stiffness to the fabric resulting in extremely poor hand.
There have been attempts to control the shrinkage of cotton garments by producing such garments oversized and then washing and tumble drying to size. This technique is feasible where the garments are expected to have a washed or stone-washed look. However, the cost of producing garments of this type is high and the appearance of the garments is mussy or worn. There have been attempts to treat fabric of 100% cotton by using washing and drying techniques to cause the cotton to shrink fully so that garments made of the pre-shrunk fabric shrink minimally or not at all. However, it is not possible using this technique to produce material on a continuous production basis since the fabric while being washed must be in relatively short lengths. There have been attempts to achieve shrinkage by moistening the fabric, subjecting it to agitation and thereafter drying by hot air on a continuous basis. This process has been only partially successful in providing shrinkage control since it is relatively impossible to provide total relaxation of the fabric during the regular production process.
An attempt has been made as shown in U.S. Pat. No. 3,597,851 (Arendt) to reduce the residual shrinkage of textile materials of relatively short pieces or of finished garments (both natural and synthetic fibers) by subjecting synthetic fabric to heat and tumbling alternatively in one direction and then in the other and by repeatedly moistening cotton material with water or steam and tumble drying after each moistening to reduce shrinkage to low levels. This process does not teach the precise control of fabric preparation and subsequent garment manufacture and shrinkage required to achieve the benefits of the present invention process. Moreover, the process described in the patent in respect to cotton fabric would produce a washed look at point-of-sale because of repeated moistenings and tumble drying.